“Practice safe phone,” Dr. Davis told me when she came into the San Francisco TechCrunchTV studio to talk about Disconnect. The truth about cell phone radiation, she explained, is that the closer we keep the phone to our bodies, the more dangerous they become. Thus keeping our phone in our trouser pocket or, god forbid, sleeping with it, is a recipe for disaster, Dr. Davis says – particularly for children who, she warns, are much more vulnerable to the long-term consequences of cell phone radiation than grown-ups.

So is Dr. Davis crazy? If she is, then so are the governments of Finland, Israel, France and Canada who are all now trying to protect their citizens from cell phone radiation. And even the Americans are beginning to wake up to the threat, with enlightened city governments in Berkeley and San Francisco now encouraging their residents to practice safe phone.